uploading and reading from an excel file in asp.net core 2

Question

previously Asp.Net MVC had this third party library which easily allowed uploading and reading from an excel file called Excel Data Reader. We didn\'t need to have the file

Answer 1

if we are talking about Razor Pages, here's a simple sample that I tested today..

Environ: .NET Core 3.1, VS 2019

A simple class

public class UserModel
{
    public string Name { get; set; }
    public string City { get; set; }
}

Index.cshtml.cs

usings..
using ExcelDataReader;

public void OnPost(IFormFile file)
    {
        List<UserModel> users = new List<UserModel>();
        System.Text.Encoding.RegisterProvider(System.Text.CodePagesEncodingProvider.Instance);
        using (var stream = new MemoryStream())
        {
            file.CopyTo(stream);
            stream.Position = 0;
            using (var reader = ExcelReaderFactory.CreateReader(stream))
            {
                while (reader.Read()) //Each row of the file
                {
                    users.Add(new UserModel { Name = reader.GetValue(0).ToString(), City = reader.GetValue(1).ToString()});
                }
            }
        }
        //users // you got the values here
}

Mark up in View

<form id="form1" method="post" enctype="multipart/form-data">
<div class="text-center">

    <input type="file" id="file1" name="file" />

</div>

<script>
    document.getElementById('file1').onchange = function () {
       document.getElementById('form1').submit();
     };
        </script>

You would require ExcelDataReader nuget package, I used 3.6.0 version

github working code

Answer 2

First upload your excel file and read the excel file record using asp.net core 3.1.

using System;
using Microsoft.AspNetCore.Mvc;
using ExcelFileRead.Models;
using Microsoft.AspNetCore.Hosting;
using System.IO;
using OfficeOpenXml;
using System.Linq;

namespace ExcelFileRead.Controllers
 {
 public class HomeController : Controller
  {

    private readonly IHostingEnvironment _hostingEnvironment;
    public HomeController(IHostingEnvironment hostingEnvironment)
    {
        _hostingEnvironment = hostingEnvironment;
    }
    public ActionResult File()
    {
        FileUploadViewModel model = new FileUploadViewModel();
        return View(model);
    }
    [HttpPost]
    public ActionResult File(FileUploadViewModel model)
    {
        string rootFolder = _hostingEnvironment.WebRootPath;
        string fileName = Guid.NewGuid().ToString() + model.XlsFile.FileName;
        FileInfo file = new FileInfo(Path.Combine(rootFolder, fileName));
        using (var stream = new MemoryStream())
        {
            model.XlsFile.CopyToAsync(stream);
            using (var package = new ExcelPackage(stream))
            {
                package.SaveAs(file);
            }
        }

        using (ExcelPackage package = new ExcelPackage(file))
        {
            ExcelWorksheet worksheet = package.Workbook.Worksheets.FirstOrDefault();
            if (worksheet == null)
            {

                //return or alert message here
            }
            else
            {

                var rowCount = worksheet.Dimension.Rows;
                for (int row = 2; row <= rowCount; row++)
                {
                    model.StaffInfoViewModel.StaffList.Add(new StaffInfoViewModel
                    {
                        FirstName = (worksheet.Cells[row, 1].Value ?? string.Empty).ToString().Trim(),
                        LastName = (worksheet.Cells[row, 2].Value ?? string.Empty).ToString().Trim(),
                        Email = (worksheet.Cells[row, 3].Value ?? string.Empty).ToString().Trim(),
                    });
                }
                
            }
        }
        return View(model);
    }

  }
}

For more details(step by step)

https://findandsolve.com/articles/how-to-read-column-value-from-excel-in-aspnet-core-or-best-way-to-read-write-excel-file-in-dotnet-core

Answer 3

I tried this code below (without using libs) for ASP.NET Core and it worked:

public ActionResult OnPostUpload(List<IFormFile> files)
    {
        try
        {
            var file = files.FirstOrDefault();
            var inputstream = file.OpenReadStream();

            XSSFWorkbook workbook = new XSSFWorkbook(stream);

            var FIRST_ROW_NUMBER = {{firstRowWithValue}};

            ISheet sheet = workbook.GetSheetAt(0);
            // Example: var firstCellRow = (int)sheet.GetRow(0).GetCell(0).NumericCellValue;

            for (int rowIdx = 2; rowIdx <= sheet.LastRowNum; rowIdx++)
               {
                  IRow currentRow = sheet.GetRow(rowIdx);

                  if (currentRow == null || currentRow.Cells == null || currentRow.Cells.Count() < FIRST_ROW_NUMBER) break;

                  var df = new DataFormatter();                

                  for (int cellNumber = {{firstCellWithValue}}; cellNumber < {{lastCellWithValue}}; cellNumber++)
                      {
                         //business logic & saving data to DB                        
                      }               
                }
        }
        catch(Exception ex)
        {
            throw new FileFormatException($"Error on file processing - {ex.Message}");
        }
    }

Answer 4

Latest versions of ExcelDataReader support netstandard2.0, thus work with ASP.NET Core 2. It also targets netstandard1.3, so works with ASP.NET Core 1.x as well.

(not sure what you searched that said it is not possible, but that is clearly wrong)

Answer 5

I Could Read Excel File In 'Asp .Net Core' By This Code.

Import And Export Data Using EPPlus.Core.

    [HttpPost]
    public IActionResult ReadExcelFileAsync(IFormFile file)
    {
        if (file == null || file.Length == 0)
            return Content("File Not Selected");

        string fileExtension = Path.GetExtension(file.FileName);
        if (fileExtension != ".xls" && fileExtension != ".xlsx")
            return Content("File Not Selected");

        var rootFolder = @"D:\Files";
        var fileName = file.FileName;
        var filePath = Path.Combine(rootFolder, fileName);
        var fileLocation = new FileInfo(filePath);

        using (var fileStream = new FileStream(filePath, FileMode.Create))
        {
            await file.CopyToAsync(fileStream);
        }

         if (file.Length <= 0)
             return BadRequest(GlobalValidationMessage.FileNotFound);  

         using (ExcelPackage package = new ExcelPackage(fileLocation))
         {
          ExcelWorksheet workSheet = package.Workbook.Worksheets["Table1"];
          //var workSheet = package.Workbook.Worksheets.First();
          int totalRows = workSheet.Dimension.Rows;

          var DataList = new List<Customers>();

          for (int i = 2; i <= totalRows; i++)
           {
                  DataList.Add(new Customers
                    {
                   CustomerName = workSheet.Cells[i, 1].Value.ToString(),
                   CustomerEmail = workSheet.Cells[i, 2].Value.ToString(),
                   CustomerCountry = workSheet.Cells[i, 3].Value.ToString()
                   });
           }

                _db.Customers.AddRange(customerList);
                _db.SaveChanges();
            }
        return Ok();
}